Electric lamp



3 Sh eets-Sheet 1 E. WESTON. Electric Lamp. No, 240,210. Patented April 12,1881.

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3 Sheets-Sheet E. WESTON. Eleotrm Lamp.

Patented April 12,1881.

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a. PETERS, FNOTO-LITHOGRA PHER, WASHINGTON, D C.

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E. WESTON. Electric Lamp..

No. 240-210. Patented April 12,1881.

H. PETERS. PNOTD-UTHOGRAFHER, WASHINGTON. D c

UNITED STATES EDlVARD \VESTON, OF NEWARK, NEW JERSEY.

PATENT OFFICE.

ELECTRIC LAMP.

SPECIFICATION forming part of Letters Patent No. 240,210, dated April 12, 1881.

Application filed July 8, 1879.

T 0 all whom it may concern Be it known that I, EDWARD WEsToN, of Newark, New Jersey, have invented certain Improvements in Electric Lamps, of which the following is a specification.

The ultimate object of my improvements is to increase the steadiness of the arc in electric lamps; and my invention relates to the several steps of the method by which I effect this object.

The first step is to augment the sensitiveness with which the electro-magnet is affected by those changes in the conditions under which it acts, which arise primarily from the com bustion of the carbons and the consequent elongation of the arc. I accomplish this result by winding the magnet differentially with two coils, one of which is embraced in the primary circuit and includes the carbons, while the other is included in a derived circuit, the proportion of the current flowing through the two circuits being automatically dependent upon the progress of combustion in the carbons, and the effect of diverting the current into the derived circuit being to weaken the attractive force of the magnet, and hence to insure the release of the carbons to the sole action of gravity.

The second step is to provide a constant balance for the carbons, so that the force which tends to bring them together will be exactly compensated for by another force which tends to hold them a prescribed distance apart. This I accomplish by so constructing the armature and magnet that during the movemen t of the armature through a considerable portion of the magnetic field the attractive force exerted upon it by the magnet remains equal, in contradistinction to the fact as regards the class of magnets and armatures ordinarily employed, in which the attractive force exerted by the magnet upon the armature rapidly increases as the distance between them (liminishes. To effect this object I either use a longitudinally-hollow core for my clectro-magnet and an armature cone-pointed, which, when attracted, is drawn into the hollow pole ofthe magnet, or a cone-pointed core and a hollow cylindricalarmature, which, when attracted, surrounds the conical end of the core. The

use of the cone in either case greatlyincreases the effectiveness of the device. By either of these modes of construction the separation of the armature and the magnet is effected without any abrupt departure of the entire armature from the field of greatest force. I am therefore enabled to so adjust the energy of the magnet that its attractive force, with at current of given strength and with an amount of resistance in the circuit due to a given length of arc, is exactly that which is required to counterbalance the weight of the carbons and carbon-holders. When thus organized the attractive force exerted by the magnet upon the armature varies directly as the strength of the operating-current employed. If the operating-current be augmented in strength, the arc will elongate, increasing the resistance in the circuit until the force of the magnet is reduced to exactly the amount required to counterbalance the force exerted upon the carbons by gravity in opposition to the force of the magnet. Hence the carbons, under all circumstances, are made to assume the positions due to an equilibrium of the two forces acting upon them in opposite directions.

The third step is to provide a clamping device, operated by the armature, capable of instantaneously griping or of being instantaneously detached from the carbon-h older. My device for this purpose consists of a jointed clamp, the two parts of which are connected by links with the forked arm of the armaturelever, so that when the forked arm of the lever rises the upper edges of the opening in the jointed clamp are made to gripe the vertical rod, to which the upper carbon is attached, and thus lift it in a vertical line exactly parallel with the lateral walls or bearings, which serve to guide its movements, and withoutincreased friction upon its bearings.

My invention includes several details of construction, among which is the support of the lower carbon-holder in or upon a metallic ring detaohably inserted in the lower end of the metallic frame of the lamp.

The accompanying drawings, representing a lamp embodying my improvements, are as follows:

Figure l is a top view of the plate upon which the adjusting mechanism of the lamp is I erected. Fig. 2 is a side elevation of the lamp,

showing the lower carbon-holder in central vertical section. Fig. 3 is a vertical section, on an enlarged scale, of the hollow differential electro-magnet and the conical armature through the line so 00 on Fig. 1. Fig. etis a vertical section of magnet with a conical pole and ahollow cylindrical armature. Fi 5 is an end elevation, on an enlarged scale, of the forked end of the armatu re-lever and the jointed clamp with which the armature-lever is connected by links, and a section through the line y y on Fig. 1 of the lower bearing of the sliding carbon-holder. Fig. 6 is a top view of thejointed clamp upon the same scale as Fig. 5. Fig. 7 is an end elevation of the armaturelever and clamp, showing a modification in the construction of the clampdetaching mechanism. Fig. Sis a top view of the modified clamp shown in Fig. 7. Fig. 9 is an endelcvation of the forked end of the armature-lever and ot' the clamping device, showing a modification in the mode of connecting the clamp with the forked end of the armature. Fig. lO is a top view of the modified clamp shown in Fig. 9.

In the lamp shown in the drawings a wooden plate or bed, A, upon the top of which thecarbon-adjusting mechanism is mounted, is intended to be suspended from above by means of the spiral springs to a. The base of the lamp is a metallic ring, B, supported upon the lower ends of the vertical metallic rods 1), the upper ends of which are secured in the centrally-perforated metallic plate A, aflixed to the under side of the wooden bed A.

The lower carbon, 0, is held by the screwclamp c in the holder O, which'is erected upon the horizontal bar C extending transversely across the ring B, detachably inserted in the ring B. The transverse bar 0 is provided with the central perforation, 0, to allow the lower carbon to be pushed upward into the lower carbon-holder. The spaces on either side of the transverse bar 0 are filled with wire-gauze to catch particles of incandescent carbon which may break off, and to partially protect the are from upward currents of air.

The upper carbon, D, is inserted in the ferrule D on the lower end of the vertical sliding rod d, which passes up through the bed A, and has its upper bearing in the top of the arched standard d, erected upon the metallic plate E, which is aftixed to the top of the wooden bed A.

The carbon-adjusting mechanism embraces the electro-magnet F, which preferably consists of two hollow cylindrical iron cores,f, each surrounded with a coil, F, which is included in the main circuit F and with a differentially-wound coil, f whichisincludedin a derived circuit, f The armature of the magnet is a horizontal iron bar, Gr, adjustably mounted upon the armaturelever g, which is transversely pivoted in the post g. Near the ends of the iron bar G, I provide upon its under side the downwardly-projecting iron cylinders G, the lower ends, G of which are preferably conical. The position of the armaturelever with reference to the electro-magnets is such that as the lever rocks the conical points G of the armattire-cylinders move in and out of the hollow poles of the cores ff of the electro-magnet.

Instead of hollow cores for the electromagnets, solid cores may be used, each having a projecting conical point, for employment in combination with a tubular armature having a range of motion enabling it to inclose the point of the core, as shown in Fig. 4.

The armature-bar G is preferably made adjustable upon the lever by means of the adjusting-screw G or by any other suitable means. It will, however, of course be understood that substantially the same effect of adjustment will be produced by making the electro-magnets vertically adj ustable. For the purpose of holding down the longer end of the armature-lever, which projects beyond the electro-m agnet, itmay be provided with the ratchetteeth g for engagement by the pawl g pivoted in arms projecting laterally from the slotted spring-standard H. The longer end of the armaturelever extends through the slot in the spring-standard H, and is secured to the lower end of the spiral spring It, the upper end of which is secured to the end of the vertical bolt h, which is vertically tltljllStttblG by means ,of the thumb-nut 7L2, so that the tension of the spiral spriugmay be varied'for the purpose of adjusting it with reference to regulating the action of the electro-magnet upon the armature.

The spring-stamlard H may be provided with two laterally-projectin g arms, H. and H, for the reception, respectively, of screws I and i, for limiting the range of movement of the armature-lever. The shorter end of the armature-lever is forked, and each branch of it is connected by means of the links J andj with the jointed clamp K. The clamp K is composed of the two forked jaws k 7., the forked ends of which are tongued together and are connected by the transverse pivots 7t 7a. The stems of the forked jaws k k are pivoted to the lower ends of the links j and j, respectively. It will be seen that when the forked jaws are thus pivoted together the open space K is left in the center of the clamp for the admission of the vertical sliding rod (1, to which the movable carbon D is attached. \Vhen thcjaws 7010 are in line with each other, in the position shown in Fig. 5, the central space, K, is sufiiciently large to loosely contain the vertical rod (1. The clamp K is supported in this position by reason of the contact of the lower ends of the pins k with the interior of the cupshaped stop K These pins are aftixcd to and project downwardly from the jaws 7t 7;,respectively. When the forked arm of the armaturelever is raised, as the clamp is then supported solely by the pivots in the ends of the stems of thejaws It It, the weight of the jaws causes their connected forked ends to drop downward, thus lessening the width of the space K and bringing the upper edges of the two jaws against the opposite sides of the vertical sliding rod d. The friction of these edges upon the sliding rod is sufficient to hold the rod and as the clamp is carried up by the armature-lever the vertical sliding rod is moved up with it, thus carrying up the upper carbon, D, and increasing the distance between the lower end or point of the movable carbon D and the upper end of the stationary carbon C.

When it is desired to permanently hold the upper carbon up-as, for example, when it becomes necessarytointroduce a new lower carbon-the longer end of the armature-lever is tilted downward and the pawl thrown over, so as to engage the ratchet-teeth 9 It will of course be understood that a cam or eccentric, or any other well-known mechanical device which will operate of itself, may be employed in place of the pawl g for the purpose of holding the longer end of the armature-lever down, and thus tilting the forked end up and holding up the upper carbon.

I In the modification in the construction of the clamp shown in Figs. 7 and S the pins k W, instead of depending vertically from the jaws of the clamp 7t" 70, are bent crosswise, and by striking against a horizontal surface as the clamp is lowered rock its central portion upward, and thus disengage it from the sliding rod d.

In the modification shown in Figs.9 and 10 a single link, J, is employed in place of the twollnks J andjfor connecting the clampingjaws respectively with each branch of the forked end of the lever.

To support a transparent globe, when it is 1 desirable to employ one for surrounding the periphery for engagement with the female screw-thread formed upon the inner side of the ring B; or the inner ring may be provided with recesses in its periphery for engagement by pins projecting inward from the ring B. The object in making the ring B detachable is to facilitate the removal of the lower carbonholder from the lamp when it is desired to introduce a new carbon.

WVhen the lamp is to be suspended from an 1 object which is liable totremorsorvibrationsas, for example, the floor of a factory where heavy machinery is operated-I employ for its suspension the spiral springs to a. It will of course be understood that if the lamp is to be supported from below it may be supported upon an elastic or spring bed. In either event the presence of the springs will serve to prevent the transmission to the lamp of the vibrations of the object upon or to which the lamp is supported or suspended.

In operating my lamp I first regulate the tension of the armature-lever spring h with reference to the electro-magnet so that the attractive force of the magnet, tending to pull down one end of the armature-lever, substantially counterbalances the weight of the clamp K, the sliding rod (7, and the movable carbon D hanging upon the other end of the armaturelever. It will thus be seen that as the resistance ot'the circuit increases, owing to the burning away of the carbons and the lengthening of the arc, the attractive force of the electromagnet decreases, and the combined weight of the clamp K, the vertical rod (1, and the carbon D, suspended upon the forked end of the armaturelever, then exercises a preponderating force and causes the movable carbonholder toet'all. In falling the lower ends of the pins k strike against the inclined inner side of the cup K and, being thus pressed toward each other, tend to rock the journal ends of the jaws It 7- upward and disengage the clamp K from the sliding rod 61, leaving the sliding rod (1 free to fall until the points of the carbons are brought together, or until, owing to the diminished resistance of the circuit, the attractive force of the electro-magnet is increased sufficiently to again attract the armature downward and raise the forked end of the lever. and thus again close the gripe of the clamp K upon the sliding rod (1.

In order to weaken the attractive force of the electro-magnet G sufficiently to prevent it from attracting its armature at the instant when the forked end of the armature-lever is relieved from apart of theweight of the clamp and from the weight of the sliding rod (1, I wind upon the electro-magnet the differential coil f, formin g a part of the derived circuit f and I provide a circuit-closer, F which is adapted to close the derived circuit, aml thus more completely depolarize the magnet whenever the resistance in the main circuit is increased to a prescribed amount by the too great separation of the carbon points.

The action of my cone-pointed armature and hollow core, or cone-pointed core and hollow armature, is so perfect that the differential winding of the magnet will not ordinarily be required, except in the case of a lamp in which both carbons are movable and are connected by gearing driven by an impelling-pawl actuated in one direction by the electro-magnet and in the other direction by gravity or by a spring, or in case several lamps are operated in series in a single circuit. In the latter case it will not be necessary to employ more than one circuitcloser, because the derived circuit may be extended and made to include the differential coils in all the lamps.

In a specification which I have prepared to accompany another application for a patent I have described an especial mode of employing its differential magnets in connection with a series of electric lamps operated in the same circuit, which consists in providing thelamps alternately with differentially-wound magnets and with magnets having supplemental coils wound in the same direction as their primary coils. lhis mode of arranging and operating the magnets is therefore not included in my present application.

To close my derived circuit I may use any of the well-known forms of circuit-closers operated by the current. I prefer, however, to use an electro-magnet similar to that which operates the movable carbon-holder, having the longitudinally-hollow cores, and having its primary coil included in the main circuit; but a supplemental coil wound in the same direction as the primary coil and included in the derived circuit may be used.

My circuit-closer may be placed upon the wooden bed A, as shown in the drawings, or it may be placed elsewhere, as may be more convenient.

When, owing to the increased resistance in the main circuit, the attractive force. of the magnet has diminished, the free end F of the armature rises and strikes against a metallic stop, F which is electrically connected with the main circuit and with one end of the derived circuit f. A fine wire is used for the derived circuit, in order that it may present an excess of resistance. After completing its successive convolutions around the cores ofthe electro-magnet N of the circuit-closer, this fine wire is carried to and wound around the coils of the electro-magnet F in the direction opposite to that of the primary coils, and is then again connected with the main circuit. The closing of the derived circuit when the resistance in the main circuit has increased, owing to the too great separation of the carbons, shunts a portion of the current through the difi'erential coil 1 and depolarizes the magnet F, thus instantly releasing the carbon-holder to the sole action of gravity.

By the lessening of the distance between the carbon points as the rod d falls, and the consequent diminution of the resistance in the main circuit, the electro-magnet F regains its attractive force and pulls down the armature Gr, tilting upward the forked end of the armature-lever, thus closing the clamp upon the sliding rod 61 and lifting the sliding rod at until the carbon points are separated to the required distance. Ooincidently the electromagnet in the circuit-closer attracts its armature, thus removing the free end F from the stop F and opening the derived circuit.

1 do not herein claim the combination of an electric lamp with a spring or springs upon which the lamp is supported or suspended, as I intend to make this part of my invention the subject of a separate application for a patent.

I claim as my invention- 1. An electro-magnet and an armature the opposed parts of which are respectively in the form of a cone and of a hollow cylinder, the armature having a range of motion permitting the cone to enter the hollow cylinder when the armature yields to the attraction of the magnet, substantially as and for the purpose described.

2. An electro-magnet having a longitudinally-hollow core, in combination with a conically-pointed movable armature havingarange of motion permitting its conical point to enter the tubular pole of the magnet, substantially as and for the purpose described.

3. In combination with an electro-magnet provided with a hollow core and a comicallypointed movable armature, an adjusting device by means of which the range of movement of the lever to which the armatureis attached may be adjusted, substantially as described.

4. In an electric lamp, the combination of a main circuit of small resistance, which includes the carbons and the principal coil surrounding the electro-magnet, with a derived circuit of large resistance, which includes a coil wound differentially upon the electro-magnet, and a circuitcloser adapted to close the derived circuit whenever the resistance in the main circuit is increased to a prescribed amount by the too great separation of the carbons, substantially as and for the purpose set forth.

5. In an electric lamp, the combination of the carbons with a difit'erential magnet the two oppositely-wound coils of which are respectively included in the main circuit, which includes the carbons, and in a derived circuit, whereby the distribution of the current in the two circuits is automatically dependent upon the progress of the combustion of the carbons, substantially as described.

6. In an electric lamp in which the force of gravity tends to diminish the distance between the points of the carbons, a lever to which at one end a movable carbon is suspended and upon which at the other end an armature is affiXed, in combination with an electro-magnet. the opposed parts of the armature and magnet being respectively conical and tubular, whereby the armature has a prescribed range of movement in the magnetic field, during the whole of which there is no material variation in the amount of attractive force exerted upon it by the magnet, substantially as and for the purpose set forth.

7. The clamp K, composed of the pivoted clamping-jaws I: k, respectively linked to the forked end of the rocking armature-lever, in combination with the vertical sliding rod d, as and for the purpose set forth.

8. The clamp K, composed of the pivoted jaws k k, the armature-lever, and links connecting the same, in combination with a stop adapted to disengage the jaws 7c from the movable carbonholder when the same has been dropped to the desired point.

9. The combination, in an electric lamp, of the vertical sliding carbon-holder at, the clamp K, the forked armature-lever g, to which the l the pawl g for holding up the end of the leclamp is linked, and an electro-magnet the ver carrying the clamp, substantially as set coils of which are included in the circuit 1 forth.

which supplies the lamp, substantially as de- EDWARD WESTON. 5 scribed. Witnesses:

10. The armature-lever g and the upper car- J. O. YOUNG, hon-holder and clamp, in combination with JOHN OTTO. 

